WASHINGTON — The first week of President Barack Obama's bid to build political unity on Syria by bringing in Congress ended in near disarray, with top Cabinet officers and Pentagon officials providing murky or even contradictory responses to inquiries from frustrated lawmakers and reporters.

The high-drama hearings, stakeouts, speeches and briefings about the U.S. military response to Syrian President Bashar Assad's alleged use of chemical weapons last month raised more questions than they answered. All the clamor on Capitol Hill, at the White House and beyond left Americans uncertain about the costs, consequences and extent of a risky intervention that is still in the works.

Analysts and lawmakers across the political spectrum were openly skeptical that Obama and his aides could make good on their repeated pledges that a U.S. strike would be of limited scope and short duration, likely delivered by Tomahawk cruise missiles and with no American troops in Syria.

"It's very difficult to hold the line at this kind of halfway position the President has proposed," said Jeremy Shapiro, a former State Department adviser under Obama who is now a fellow at the Brookings Institution in Washington. "This is a very important step down a slippery slope, and it's unlikely to be the last step."

Despite Secretary of State John Kerry's assurances to Congress during two days of testimony that "the president is not asking you to go to war," a bipartisan consensus emerged that once the bombs start flying, all bets are off — especially in a country like Syria, torn by two years of civil strife and, more broadly, in a region as volatile as the Middle East.

In a town where Democrats and Republicans can't agree on the time of day, there was an odd concurrence between the objections raised by lawmakers from the two parties.

"I think there's a reasonable argument that the world may be less stable because of this, and that it may not deter another chemical weapons attack," Sen. Rand Paul, R-Ky., told Kerry.

"Iraq is as violent today as any time in its history, and Afghanistan is as poor and corrupt as it's always been," Rep. Brian Higgins, D-N.Y., told Kerry. "The American people are sick and tired of war. It's time to nation-build in America and invest in the growth of the American economy."

While Obama won a compromised victory with narrow passage of a war resolution by the Senate Foreign Relations Committee, senators from his own party defected. And the man Obama defeated in the 2008 presidential election, maverick Republican Sen. John McCain of Arizona, raised red flags by inserting a clause defining one of the U.S. mission's purposes as "change the momentum on the battlefield in Syria," an ambitious goal that seems beyond the reach of a limited missile strike with no American troops in place.

Much of the damage to Obama's cause was self-inflicted by the men he dispatched to Capitol Hill.

Kerry began his testimony by saying no U.S. warriors would set foot in Syria. But he then sketched a compelling scenario — one in which, he said, "Syria imploded" or chemical weapons might be close to "falling into the hands" of al-Qaida-linked rebels — that might require them to do so. That set off a fusillade of questions from lawmakers about the apparent contradiction, forcing him to backtrack quickly.

In the coming days, "no boots on the ground" became the Obama team's mantra. At a Pentagon briefing Thursday, Defense Secretary Chuck Hagel's spokesman, George Little, used the phrase 18 times in 45 minutes, uttering it so often that reporters dubbed the Syria mission Operation No Boots On the Ground.

But even Little's disciplined attempt to toe the official line was hedged at times.

"We are not contemplating boots on the ground at this time in any way, shape or form," he said at one point.

"There are no plans at this time for boots on the ground," he said a few minutes later.

In Washington-speak, the phrase "no plans at this time" can mean "it will happen later," as when lawmakers assure constituents they have "no plans at this time" to run for President, but later find themselves in the snows of New Hampshire or Iowa after plans have changed and time has moved on.

Hagel himself caused some problems when saying, in response to a House member's question, that the contemplated Syria strike would cost in the "tens of millions" of dollars, a price tag that analysts jumped on as laughably low for even the most limited strike on Assad.

Mattea Kramer, an analyst who tracks military spending with the National Priorities Project in Northampton, Mass., said the 2011 NATO bombing campaign in Libya cost the United States more than $1 billion.

"Outside of the Pentagon, no one truly knows what the contours of this mission will be," she said. "But it's hard to imagine how the price would be anything close to as low as tens of millions of dollars given the cost of the missiles (likely to be used) and what we know about Libya."

Kerry also raised eyebrows when he testified that 15 percent to 25 percent of the Syrian opposition fighting Assad is made up of "bad guys" _ radical Islamists, many with al-Qaida ties. That range flew in the face of much higher figures provided to lawmakers by intelligence agencies.

Bruce Riedel, who served under five presidents as a CIA counterterrorism expert, said foreign fighters linked to al-Qaida have been flowing into Syria to take up the fight against Assad and that a U.S. strike against the regime would only strengthen them more.

"We should have no illusion that at the end of the day, the more we weaken Bashar Assad, the more we're going to end up having a bigger al-Qaida problem in the future," said Riedel, now a Brookings analyst.